问题
选择题
______ their homework, these three students have to stay in the classroom for another thirty minutes.
A．Not finishing
B．Not finished
C．Having not finished
D．Not having finished
答案
答案：D
考查非谓语动词。句意：（由于）没有完成他们的作业，这些学生不得不在教室里再呆三十分钟。现在分词作原因状语表示正在进行的伴随性动作，如果动作发生在谓语动词之前，则用完成时态的过去分词，故选D。